If you’re one of those readers who cringes when you encounter a typo or — horrors!— a grammatical error, you’ll want to skip this article on Yahoo! Style. The writer seems to have a problem with a common rule we all learned in third grade:
Perhaps the writer didn’t know if she was writing about one star (and therefore should use star’s) or more than one (requiring stars’). So, she combined the possessives into misguided mashup.